Apparatus for locating uncemented portions of well casings



March 16, 1954 Filed March 8, 1950 B. w. SEWELL 2,672,050

APPARATUS FOR LOCATING UNCEMENTED PORTIONS OF WELL CASINGS 2Sheets-Sheet 1 ben 55M611 {Sax/ember h5g1 0. 7 abhor nag March 16, 1954B. SEWELL 2,672,050

APPARATUS F LOCATING UNCEMENTED L PORTIONS OF WELL CASINGS Filed March8, 1950 2 Sheets-Sheet 2 P SI F51. us WW/WA 32 E I G '2 ban. CJTSecJeZZUnverzbor' b k Qbtorneg Patented Mar. 16, 1954 i I APPARATUS FORLOCATING UN 'CEMEN'I ED PORTIONS OF WELL CASINGS Ben W. Sewell, Tulsa,Okla; assignor to Standard Oil Development Company, a corporation ofDelaware Application Marcus, 1950, Serial No. 1,413,289

4 Claims. 1

This invention relates to anapparatus for determining the successfulcrunsuccessful cementing of a casing in a well. The apparatus isprimarily intended for application in oil wells. By means of thisinventionfit is possible to determine What portions of a well casingare, or are not properly cemented in the well.

One of the most important problems in successfully producing oil, or gasfrom a well relates to the successful exclusion of water from theproductive formations. Again, it is generally desirable, particularly inthe case of deep wells, to protect the well casing from the tremendouscollapsing pressure which may exist in the well. These and otherdesirable objectives are conventionally attained by cementing the casingin the well bore hole. It is apparent, however, that in order tosuccessfully obtain the benefits of oil well cementing, it is necessaryto know the extent to which cement has extended behind the casing, andto know to What portions of the easing cement has not extended. Thepresent invention is directed to this specific objective; that is, toprovide operators with information as to what portions of a well casingare properly cemented, or conversely what portions of the well casingare not properly cemented.

' The apparatus of this invention, to achieve this objective, applies aninternal deforming force to the well casing. In the case in which thewell casing is not cemented, the deforming force can cause the casing toassume an ellipti: cal, rather than a circular cross-section. However,in the case in which the well casing is properly cemented in the borehole, the cement will provide sufficient lateral support to the wellcasing so that comparatively little or no deformation will occuron'application of the deforming force. l p

The apparatus of this invention by which the indicated method may besuccessfully conducted consists of two wheel like members adapted toroll along opposing sides of the interior of a well casing. At least oneof these wheel like members is so controlled by a hydraulic force, thatit can be forced away from the other of the wheel like members sothattogether the two members can exert a deforming force on the cas ing.The apparatus includes means for period? cally forcingat least one ofthewheellikeiiienibers away rrom'fme other fo'f the members? andincludes means" for measuring. tl'ie foroev thus applied, and means'for"measuringthefielative displacement. of the two wheel,likemempfii-s.. 'Itisapparent that'knowin'g the fbrce aii pli e d as a mechanical deformingforce to the casing, the relative displacement of the two wheel likemam: bers applying the force will indicate the deformation of the casingin response to this force. Thus, it is possible to tell when the casinghas deformed sufficiently under a given force to show that the casing isnot cemented in the bore hole, or whether so little deformation occursthat the casing is shown to beproperly cemented.

In order to more clearly exemplify the concepts of this invention, apreferred embodiment of the apparatus constructed in accordance withthis invention is illustrated in Figures 1 and 2, of the attacheddrawings. In these figures-Figure 1, corresponds to the upper portion ofthe apparatus to be passed down awell casing, while Figure 2, shows alower portion of this same apparatus, being a continuation of the viewshown in Figure l. Jointly, the figures represent a complete andintegral cement fault locator.

In thesefigures the numeral 30 designates a well bore hole drilled intothe earth. The numeral 3] shows a well casing which has been placed inthe bore hole. In'the annular space around the casing 31 and within thebore hole 30, it is assumed that cement has been positioned. This cementmay be inserted in the annular space in any desired manner, or accordingto conventional practices in this regard. For the present purposes itmay be assumed that cement has successfully penetrated the annular spacearound the casing,except for a portion of the casing adjacent theparticular stratum 32. It is apparent, therefore, that the casing 3|will be bound by, or laterally supported by this cement parts required.This housing may suitably be supported in thewellby a cable 5, so thatit can be lowered down 'intothe casing and may be pulled back to the"surface" of the earth in order to survey the extent "and" sufficiencyof prior cementing operations. An electric motor 1' may be emplo'yedtoprovide the energy required to eri ical :a i rd m e l r s i t r casing3i. The electric motor [may be driven by a atten '6 c rrieqimthe a a uor it may be drive H power lines running through cable .5. tothe..'$l1rface' ,of v.thegfearth. The shaft of th''motor"l"is'coiinectdto a suitable gear assembly 8 that drives a crank arm 9 totranslate the rotational motion of the motor shaft to a reciprocatingmotion suitable for driving the piston of the hydraulic pump I0. Anintake check valve I2 is associated with the pump I so that on theupstroke of the piston of the pump, fluid may be pulled inwardly throughvalve I2 from the hydraulic reservoir or sump I3 into the pump. On thedownward stroke of the piston, the fluid sucked in through valve I2 willbe compressed by the piston to provide hydraulic pressure which may beused to deform the well cas ing. Thus a hydraulic cylinder I4 isassociated with the pump I0. The hydraulic cylinder I I contains apiston rod, and piston combination directly connected to a rotary wheelmember I5. A second rotary wheel member I5 may be fixed to the oppositeend of the hydraulic cylinder I4, or if desired, may similarly beprovided with a piston rod and piston arrangement. The effect of thisconstruction is that when the piston of pump I0 moves downwardlyhydraulic pressure is built up in the cylinder I4 to force the membersI5 and I5 against opposite sides of the casing 3I. By this means it ispossible to periodically apply a deforming force to this casing. It ispreferred, but it is not essential, that a relief valve ll be associatedwith the pump In so that the hydraulic pressure built up in the cylinderI4 cannot exceed a predetermined value for which the release valve IImay be set.

The remaining portion of the apparatus illustrated may consist of anydesired means for measuring the force applied to the casing, and tomeasure the actual deformation of the casing. In other words, means arerequired to measure the force with which wheels I5 and I5 are forcedoutwardly from each other against the casing, and means are required todetermine how much the casing yields under the applied force. A suitablemeans for accomplishing this is to run a hydraulic tap from cylinder I 4to a bellows actuated recording pen I8. By this arrangement movements ofthe pen I8 will be controlled by the pressure in the cylinder I4 actingto control the expansion of the bellows I 6. In a somewhat similarfashion the deformation of the casing may be indicated by recording penI9, actuated by bellows I"! of the hydraulic bleeder line connected tothe hydraulic cylinder I I between the cylinder head of the cylinder,and the side of the piston opposite to the side to which hydraulicpressure is applied. Bellows H, the bleeder line, and the opening withinthe cylinder I4 to which the bleeder line has entry may be filled with ahydraulic fluid so that the movements of wheel I5 and its associatedpiston will change the hydraulic pressure in bellows H to actuate thepen I9.

It is preferred that the recording paper associated with recording pensI8 and I9 be driven by a wheel running along the casing wall. By thismeans it is possible to calibrate the record paper directly in terms ofwell depth so that the depth in the well at which a particulardeformation is encountered may readily be determined. For this purpose,therefore, a wheel 2I may extend outside the housing I to roll along thecasing 3I. This measuring wheel may drive suitable gears asdiagrammatically illustrated to cause the rotation of record paper 20.It is a preferred feature of the gear drive illustrated that a clutch 22is employed which will cause the paper to turn only when the wheel 2I isturned either clockwise or counterclockwise, as desired. Thus, as

illustrated the teeth of the clutch 22 are such that when the apparatusis passed downwardly in the well, the friction of the record paper drivewill be suflicient so that the clutch teeth will simply slip over eachother without turning the paper. However, when the apparatus is pulledupwardly in the well, the teeth will engage and turn the record paper.

It is apparent that should it be desired, suitable electrical expedientsmay be used to provide electrical signals indicating the deforming forceapplied to the casing, and the deformation of the casing, for recordingat the surface of the earth through leads which may be carried in cable5. Again, by such an expedient, electrical signals can be directlyproduced for recording in the apparatus.

The manner in which the apparatus described indicates improper cementingmay be understood by reference to the portions of the records indicatedon record paper 29. As shown, the pen I8 indicates a continuouslycycling hydraulic pressure variation sinusoidally changing from amaximum to a minimum. It is apparent that when the casing 3I is properlybacked by cement, the hydraulic pressure applied to the casing andrecorded by pen I8 will be insufficient to materially deform casing 3I.Consequently, wheel I5, and its associated piston will not be movedoutwardly enough to follow the variations in hydraulic pressure appliedto the piston. In other words, pen I9 will draw a substantially straightline as shown in the lower portions of the record produced. However, ifthe casing 3| is not properly cemented in the bore hole, as adjacentstratum 32 for example, then on application of the hydraulic pressure incylinder I4, wheel I5 will move outwardly to deform the casing. Thisthen will alter the hydraulic pressure in bellows I'I causing pen I9 todraw a sinusoidal curve similar to that drawn by pen I8. Consequently,by inspection of a record such as that diagrammatically indicated, theapparatus of this invention indicates portions of the casing which arenot properly cemented by the sinusoidal type line produced by pen I9 inthis case.

What is claimed is:

1. An apparatus for locating uncemented portions of a well casing inplace in a bore hole comprising a housing adapted for lowering into thecasing, said housing including a hydraulic reservoir, a cylinder held inan essentially horizontal position by said housing, said cylinder havingan interior chamber, a piston slidably held in chamber, a firstprojection on said piston e:-: tending laterally from said housing, aspring behind said piston urging said projection into contact with thewall of said casing, a second projection carried by said housing in thegeneral vicinity of and on the opposite side from said first projectionand extending laterally from said housing into contact with the oppositewall of said casing, a reciprocating pump communicating with saidhydraulic reservoir, a conduit conmeeting said pump with said interiorchamber behind said piston, drive means for periodically reciprocatingsaid pump whereby a periodically varying force of known periodicity isproduced within said chamber, and means for recording the extent oflateral motion of said piston with respect to said housing as a resultof deformation of said casing whereby said lateral motion may becompared with the known periodicity of the force.

2. Apparatus according to claim 1 wherein said lateral motion recordingmeans comprises an expansible bellows, a conduit connecting said bellowswith said interior chamber on the side of said piston that carries saidfirst projection, a reciprocating scriber actuated by said bellows, amovable record medium contacted by said scriber and means for movingsaid record medium past said scriber.

3. Apparatus according to claim 2 in which said means for moving saidrecord medium past said scriber includes a wheel rotatably held by saidhousing in frictional engagement with the Wall of said casing wherebysaid record medium will most past said scriber in proportion to themovement of said housing lengthwise of said 15 2,4 20

casing.

4. Apparatus according to claim 2 including pressure change measuringmeans comprising a second expansible bellows, an additional conduitconnecting said bellows with said interior chamher behind said pistonand a second reciprocating scriber actuated by said second bellows, saidsecond scriber contacting said record medium.

BEN W. SEWELL.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 974,867 Eddy Nov. 8, 1910 2,150,070 Kregecz Mar. 7, 1939 PelanJune 28, 1949 2,552,433 7 Kirby May 8, 1951

